Catalyst composition and processes therefor and therewith

ABSTRACT

A composition comprises silicon, aluminum, zirconium, and boron. A process for producing the composition comprises contacting a silicon compound, an aluminum compound, a zirconium compound, and a boron compound under a condition sufficient to effect the production of a composition comprising silicon, aluminum, zirconium, and boron. Also disclosed is a process for catalytically cracking a hydrocarbon-containing fluid which comprises contacting said hydrocarbon-containing fluid with a catalyst composition which comprises silicon, aluminum, zirconium, and boron.

FIELD OF THE INVENTION

This invention relates to a composition comprising silicon, aluminum,zirconium, and borate, to a process for producing the composition, andto a process for using the composition.

BACKGROUND OF THE INVENTION

A number of catalytic cracking catalysts such as zeolites are well knownto those skilled in the art. Recently a composition comprising aluminum,zirconium, and borate is also known to be an effective catalyticcracking catalyst. See, for example, U.S. Pat. No. 5,618,407. Acatalytic cracking generally involves steam and a catalytic crackingcatalyst is generally regenerated in the presence of steam. Thehydrothermal stability of the composition comprising aluminum,zirconium, and borate is generally not as good as one skilled in the artdesires. Therefore, it appears there is an ever-increasing need todevelop a catalyst which comprises aluminum, zirconium, and borate andis more hydrothermally stable.

SUMMARY OF THE INVENTION

An object of this invention is to provide a composition which comprisesborate. Also an object of this invention is to provide a process forproducing this composition. Another object of this invention is toemploy this composition in a process for catalytically crackinghydrocarbons. An advantage of the invention is that the composition hasgood hydrothermal stability and product selectivity. Other objects andadvantages will become apparent from the detailed description and theappended claims.

According to a first embodiment of this invention, a composition isprovided which comprises aluminum, silicon, zirconium, and borate.

According to a second embodiment of this invention, a process isprovided which comprises contacting a silicon compound, an aluminumcompound, a zirconium compound, and a boron compound under a conditionsufficient to effect the production of a solid material comprisingsilicon, aluminum, zirconium, and borate.

According to a third embodiment of this invention, a process which canbe used for catalytically cracking a hydrocarbon or a mixture ofhydrocarbons is provided. The process comprises contacting a firsthydrocarbon-containing fluid with a catalyst composition under acatalytic cracking condition effective to a produce a secondhydrocarbon-containing fluid in which the molecules or molecular weightof the hydrocarbons in the second hydrocarbon-containing fluid aresmaller than those in the first hydrocarbon-containing fluid.

DETAILED DESCRIPTION OF THE INVENTION

According to the first embodiment of the invention, the composition ofthis invention comprises, consists essentially of, or consists of,silicon, aluminum, zirconium, and borate.

Generally, the composition can have a mole ratio of Si to Zr in therange of from about 0.001:1 to about 30:1, preferably about 0.01:1 toabout 25:1 and most preferably 0.05:1 to 20: 1; a mole ratio of Al to Zrin the range of from about 0.001:1 to about 300:1, preferably about 001:1 to about 250:1, and most preferably about 0.1:1 to about 200: 1;and a mole ratio of (Al+Zr) to B in the range of from about 0.01:1 toabout 10:1, preferably about 0.1:1 to about 6:1, and most preferablyabout 0.5:1 to about 3:1. Generally, the composition has a surface area,measured by the BET method employing N₂, of about 200 to about 400 m² /gand a pore volume, measured by a pore size distribution method employingN₂, of about 0.2 to about 1.5 cc/g.

The composition can be of any suitable shape such as spherical,cylindrical, trilobal or irregular, or combinations of two or morethereof. It also can have any suitable particle size. The presentlypreferred size is about 0.001 to about 1.0 mm, preferably about 0.01 toabout 0.8 mm, and most preferably 0.01 to 0.5 mm. If particles of thecomposition have been compacted and extruded, the formed cylindricalextrudates generally have a diameter of about 1 to about 4 mm and alength of about 3 to about 10 mm. It is within the scope of thisinvention to have minor amounts of aluminum oxide and zirconium oxide,generally about 1 to about 5 weight % of each, present in thecomposition.

The composition can be produced by combining a silicon compound, analuminum compound, a zirconium compound, and a boron compound under acondition effective to produce a solid material. The composition of thepresent invention is prepared by a method comprising coprecipitation.Generally any silicon compound, aluminum compound, zirconium compound,and boron compound which can be combined to form a solid material,preferably to form a coprecipitate, can be used in the presentinvention.

Examples of suitable silicon compounds include, but are not limited to,tetraethyl orthosilicate (tetraethoxysilane), tetrabutyl orthosilicate,tetrapropyl orthosilicate, or combination of two or more thereof. Anumber of well known silylating agents such as trimethylchlorosilane,chloromethyldimethylchlorosilane, N-trimethylsilylimidazole,N,O-bis(trimethylsilyl)acetamide,N-methyl-N-trimethylsilyltrifluoroacetamide,t-butyldimethylsilylimidazole, N-trimethylsilylacetamide,methyltrimethoxysilane, vinyltriethoxysilane, ethyltrimethoxysilane,propyltrimethoxysilane, (3,3,3-trifluoropropyl)trimethoxysilane,[3-(2-aminoethyl)aminopropyl]trimethoxysilane,cyanoethyltrimethoxysilane, aminopropyltriethoxysilane,phenyltrimethoxysilane, (3-chloropropyl)trimethoxysilane,(3-mercaptopropyl)trimethoxysilane, (3-glycidoxypropyl)trimethoxysilane,vinyltris(β-methoxyethoxy)silane,(γ-methacryloxypropyl)trimethoxysilane, (4-aminopropyl)triethoxysilane,[γ-(β-aminoethylamino)propyl]trimethoxysilane,(γ-glycidoxypropyl)trimethoxysilane,[β-(3,4-epoxycyclohexyl)ethyl]trimethoxysilane,(β-mercaptoethyl)trimethoxysilane, (γ-chloropropyl)trimethoxysilane, andcombinations of two or more thereof can also be employed. The presentlypreferred silicon-containing compound is tetraethyl orthosilicate.

Examples of suitable aluminum compounds include, but are not limited toaluminum nitrate, aluminum chloride, aluminum bromide, aluminumphosphate, trimethyl aluminum, triethylaluminum, diethylaluminumchloride, and combinations of two or more thereof.

Examples of suitable zirconium compounds include, but are not limitedto, zirconium acetylacetonate, zirconium citrate, zirconium acetate,zirconium bromide, zirconium chloride, zirconium butoxide, zirconiumnitrate, zirconium silicate, zirconium sulfate, zirconium tungstate,zirconyl ethylhexanoate, zirconyl nitrate, zirconyl chloride, zirconylbromide, and combinations of two or more thereof.

Examples of suitable boron compounds include, but are not limited to,boric acid, trimethyl boroxine, triethyl boroxine, tripropyl boroxine,and combinations of two or more thereof.

According to the second embodiment of this invention, a first solutionor dispersion comprising a silicon compound such as, for exampletetraethoxysilane; an aluminum compound such as, for example, aluminumnitrate; a zirconium compound such as, for example, zirconyl nitrate;and an acidic boron compound such as, for example, a boric acid,preferably H₃ BO₃, is prepared. Any suitable concentrations of thesecompounds in the aqueous solution can be employed so long as theconcentration can result in the production of the composition disclosedabove in the first embodiment of this invention. Generally about 0.002to about 1 mole/l of each compound, depending on the desired Si/Al/Zr/Bratio can be employed. The initial pH of this aqueous solution isgenerally about 1 to about 3. Each of the above compounds is present ina liquid medium.

If a homogeneous solution cannot be formed because of water-insolublesolvent is employed, a surfactant can be used.

Generally, the surfactant comprises one or more compounds which exhibitsurface-active properties. A preferred surfactant for use in thereaction system of this invention is selected from the group consistingof alkoxylated compounds, quaternary ammonium salts, alkali metal alkylsulfates, alkali metal salts of alkanoic acids, alkali metal salts ofalkaryl sulfonic acids, 1-alkyl pyridinium salts, and combinations oftwo or more thereof.

According to the second embodiment of this invention an aqueous alkalinesolution generally having a pH of about 10 to about 14 is then added tothe first solution in an amount sufficient to raise the pH of the firstsolution to 7 or above 7, preferably to about 8 to about 9, to affordthe coprecipitation of borates of silicon, aluminum and zirconium.Although any alkaline solution can be used, it is presently preferred toemploy an aqueous solution of ammonia containing about 25 to about 28weight % NH₃.

The dispersion of the formed coprecipitate in the pH-adjusted solutionis then subjected to any suitable solid-liquid separation methods knownto one skilled in the art such as, for example, filtration tosubstantially separate the coprecipitate from the aqueous solution.Preferably, the coprecipitate is washed with water to remove adheredsolution therefrom, optionally followed by washing with a water-solubleorganic solvent such as methanol, ethanol, isopropanol, acetone, orcombinations of two or more thereof. The presently preferred solvent isisopropanol. The washed coprecipitate is generally dried by any methodsknown to one skilled in the art. The presently preferred drying is in avacuum oven, under any pressure, at a temperature of about 110 to about180° C. for about 1 to about 16 hours.

The dried solid is then calcined by any methods known to one skilled inthe art. Generally calcination can be done in air, at a temperature ofabout 300 to about 1000° C., preferably about 350 to about 750° C., andmost preferably 450 to 600° C., for about 1 to about 16 hours. It iswithin the scope of this invention to mix the formed coprecipitate witha carbon-containing binder material, such as a polyglycol, apolyoxazoline or carbon black, which is substantially burned off duringthe calcining step, and/or with an inorganic binder material such as,for example, alumina, colloidal alumina, clay, calcium aluminate, waterglass or combinations of two or more thereof. It is also within thescope of this invention to extrude or pelletize or tablet thecoprecipitate, with or without a binder, before the calcination.

A zeolite can also be incorporated into the composition of thisinvention for use as a cracking catalyst. The zeolite component, ifpresent in the cracking catalyst composition, can be any natural orsynthetic crystalline aluminosilicate zeolite which exhibits crackingactivity. Non-limiting examples of such zeolites are faujasite,chabazite, mordenite, offretite, erionite, Zeolon, zeolite X, zeolite Y,zeolite L, zeolite ZSM-4, zeolite ZSM-5, zeolite ZSM-11, zeolite ZSM-12,zeolite ZSM-23, zeolite ZSM-35, zeolite ZSM-38, zeolite ZSM-48, andcombinations of two or more thereof. Additional examples of suitablezeolites are listed in U.S. Pat. No. 4,158,621, disclosure of which isincorporated herein by reference. The term "zeolite", as used herein,includes zeolites which have been pretreated, such as those from which aportion of aluminum has been removed from the crystalline framework, andzeolites which have been ion-exchanged with rare earth metal or ammoniumor by other conventional ion-exchange methods. The term "zeolite", asused herein, also includes essentially aluminum-free silica polymorphs,such as silicalite, chromiasilicates, ferrosilicates, borosilicates, andthe like, as disclosed in U.S. Pat. No. 4,556,749, disclosure of whichis incorporated herein by reference. Generally, the zeolite component ofthe catalytic cracking catalyst composition is embedded in a suitablesolid refractory inorganic matrix material, such as alumina, silica,silica-alumina (presently preferred), clay, aluminum phosphate,magnesium oxide, mixtures of two or more of the above-listed materials,and the like. Generally, the weight ratio of zeolite to matrix materialin the catalytic cracking catalyst composition is in the range of fromabout 0.01:1 to about 1:1. The weight ratio of zeolite, if present, tothe composition of the invention can be in the range of from about0.01:1 to about 1:1.

It is within the scope of this invention to mix the formed coprecipitatewith a zeolite and/or with at least one carbon-containing bindermaterial, such as polyglycol, a polyoxazoline or carbon black which issubstantially burned off during the calcining step, and/or with aninorganic refractory binder material such as alumina, silica,silica-alumina, aluminum phosphate, clays, other known inorganicbinders, and combinations of two or more thereof. It is also within thescope of this invention to disperse zeolite(s) and/or binder material(s)in the first solution described above before the alkaline aqueoussolution described above is added to form an intimate mixture ofSi/Al/Zr borate and zeolite and/or binder(s). It is within the scope ofthis invention to extrude or pelletize the Si/Al/Zr borate-containingmaterial before the calcination.

According to the present invention, the Si/Al/Zr borate-containingcatalytic cracking catalyst composition, which may or may not comprise azeolite component and/or a binder component, is used in any catalyticcracking process such as, for example, a process for catalyticallycracking hydrocarbon-containing oil feedstocks, in any suitable crackingreactor. The term "catalytic cracking", as used herein, implies thatessentially no hydrocracking occurs and that the catalytic crackingprocess is carried out with a hydrocarbon-containing fluid feedsubstantially in the absence of added hydrogen gas, under suchconditions to obtain at least one liquid product stream having a higherAPI gravity (measured at 60° F.) than the feed. The Si/Al/Zrborate-containing catalyst composition can be used alone or in admixturewith fresh or used zeolite-containing catalyst composition in catalyticcracking processes. The term "fluid" used herein refers to gas, liquid,vapor, or combinations of two or more thereof.

The hydrocarbon-containing fluid feed stream for the catalytic crackingprocess of this invention can be any suitable feedstock. Generally, thefluid feed has an initial boiling point (ASTM D1160) of at least about300° F., and preferably has a boiling range of from about 400° F. toabout 1200° F., more preferably a boiling range of about 500° F. toabout 1100F., measured at atmospheric pressure conditions. Generally,this feed contains metal impurities, particularly nickel and vanadiumcompounds, generally in excess of about 0.01 ppm Ni and in excess ofabout 0.01 ppm V. The API gravity (measured at 60° F.) generally is inthe range of from about 5 to about 40, preferably from about 10 to about35. Generally, these feedstocks contain Ramsbottom carbon residue (ASTMD524; usually about 0.1 to about 20 weight %), sulfur (generally about0.1 to about 5 weight % S), nitrogen (generally about 0.05 to about 2weight % N), nickel (generally about 0.05 to about 30 ppm Ni, i.e.,about 0.05 to about 30 parts by weight of Ni per million parts by weightof oil feed) and vanadium (generally about 0.1 to about 50 ppm V, i.e.,about 0.1 to about 50 parts by weight of vanadium per million parts byweight of the fluid feed). Small amounts (generally about 0.01 to about50 ppm) of other metal impurities, such as compounds of Cu, Na, and Femay also be present in the oil feed. Non-limiting examples of suitablefeedstocks are light gas oils, heavy gas oils, vacuum gas oils, crackerrecycle oils (light cycle oils and heavy cycle oils), residua such asdistillation bottoms fractions, and hydrotreated residua such ashydrotreated in the presence of Ni, Co, Mo-promoted alumina catalysts,liquid coal pyrolyzates, liquid products from the extraction orpyrolysis of tar sand, shale oils, heavy fractions of shale oils, andthe like. The presently most preferred feedstocks are heavy gas oils andhydrotreated residua.

Any suitable reactor can be used for the catalytic cracking process ofthis invention. Generally, a fluidized-bed catalytic cracking (FCC)which can contain one or more risers or a moving-bed catalytic crackingreactor such as a Thermofor catalytic cracker is employed. Preferably,the reactor is a FCC riser cracking unit. Examples of such FCC crackingunits are described in U.S. Pat. Nos. 4,377,470 and 4,424,116,disclosure of which is incorporated herein by reference. Generally acatalyst regeneration unit for removal of coke deposits is combined withthe FCC cracking unit, as is shown in the above-cited patents.

Any catalytic cracking conditions known to one skilled in the art can beemployed. Specific operating conditions of the cracking operationgreatly depend on the type of feedstock, the type and dimensions of thecracking reactor and the fluid feed rate. Examples of operatingconditions are described in the above-cited patents and in any otherpublications. In an FCC operation, generally the weight ratio ofcatalyst composition to hydrocarbon-containing fluid feed can range fromabout 0.01:1 to about 20:1 and preferably 0.02:1 to about 10:1, thecontact time between hydrocarbon-containing fluid feed and catalyst isin the range of from about 0.2 to about 2.0 seconds, and the crackingtemperature is in the range of from about 800° to about 1200° F.Generally, steam can be added with the fluid feed to the FCC reactor toaid in the dispersion of the hydrocarbon as droplets. Generally, theweight ratio of steam to the fluid feed can be in the range of fromabout 0.001:1 to about 1:1.

The separation of the cracking catalyst composition from gaseous andliquid cracked products, in particular hydrocarbons, and the separationof cracked products into various gaseous and liquid product fractionscan be carried out by any well known, conventional separation means. Themost desirable product fraction is gasoline (ASTM boiling range: about80-400° F.). Non-limiting examples of such separation schemes areshowing in "Petroleum Refining" by James H. Gary and Glenn E. Handwerk,Marcel Dekker, Inc., 1975.

Generally, the used cracking catalyst composition which has beenseparated from cracked gaseous and liquid products such as in a cycloneis then regenerated, preferably by steam-stripping for removal ofadhered hydrocarbon and by subsequent heating under oxidizing conditionsso as to burn off carbon deposits by conventional means. Thereafter, theregenerated catalyst is recycled to the catalytic cracking reactor,generally in admixture with fresh (unused) cracking catalyst.

It is within the scope of this invention, to add at least one knownpassivating agent such as compounds of antimony, bismuth, tin,zirconium, tungsten, boron, phosphorus, and combinations of two or morethereof to the hydrocarbon-containing fluid feed stream before the fluidfeed enters the catalytic cracking reactor to alleviate detrimentaleffects of metal impurities, particularly compounds of nickel andvanadium present in the fluid feed. As is well known, the passivatingagent can be injected either directly into the fluid feed or into aslurry recycle stream, the highest boiling fraction of cracked products,generally containing dispersed catalyst fines, which is then combinedwith fresh oil feed, or the passivating agent can be injected into theoxidative regenerator as above where the agent comes in contact with thehot regenerated catalyst.

The following examples are provided to further illustrate this inventionand are not to be construed to unduly limit the scope of this invention.

Control catalyst A was an Al/Zr borate prepared as follows: 13.2 grams(0.053 moles) of ZrO(NO₃)₂.2H₂ O and 222.1 grams (0.592 moles) ofAl(NO₃)₃.9H₂ O were mixed with 40.81 grams (0.660 moles) of H₃ BO₃(boric acid) and 1.5 liter of distilled water. The mixture was heatedand stirred until all solids were dissolved.

Thereafter, concentrated aqueous ammonia was added to the entiremixture, which had a pH of about 2, until the pH rose to 8.4 and anAl/Zr/borate coprecipitate was formed. The filter cake was washed withabout 1.5 liter of distilled water and then with 1.5 liter ofisopropanol. The solid filter cake was dried at 150° C. for about 16hours (overnight) in a vacuum oven, followed by calcining in air at 500°C. for 4 hours. The calcined Al/Zr borate material had a surface area,measured by the BET method using N₂ of 382 m² /g and a pore volume,measured by a N₂ pore size distribution method, of 0.5 cm³ /g. Itcontained 30.0 weight % Al, 8.4 weight % Zr and 11.0 weight % B (boron).

A series of runs were then carried out the same as described above forproducing catalyst A with the exception that liquid tetraethoxy silanewas also used to produce catalysts B to I. The mole quantities ofzirconyl nitrate, aluminum nitrate, and tetraethoxy silane are shown inTable I below. The compositions had a constant total moles of elements(Zr+Al+B+Si) and boron while having variable moles of Zr, Al, Si, Zr/Al,and (Zr+Si).

A second series of runs for producing catalysts J-R is shown in TableII. The compositions in Table II had a constant total moles of elements(Zr+Al+B+Si), B, Al, and (Zr+Si), and had a variable moles of Zr, Si,and Zr/Al.

                                      TABLE I                                     __________________________________________________________________________    Catalyst Compositions with Constant Total Moles of Metal, B                   And Variable Moles of Zr, Al, Si, Al/Zr, Si/Zr, (Al + Zr)/B, and Zr +         Si*                                                                                                            Total Metal,                                 Catalyst                                                                          Zr Al B  Si Al/Zr                                                                             Si/Zr                                                                            (Al + Zr)/B                                                                         Zr + Si                                                                           Moles                                        __________________________________________________________________________    A   0.053                                                                            0.592                                                                            0.660                                                                            0.000                                                                            11.170                                                                            0.000                                                                            0.977 0.053                                                                             1.3                                          B   0.045                                                                            0.590                                                                            0.660                                                                            0.005                                                                            13.111                                                                            0.111                                                                            0.962 0.050                                                                             1.3                                          C   0.091                                                                            0.529                                                                            0.660                                                                            0.020                                                                            5.813                                                                             0.220                                                                            0.939 0.111                                                                             1.3                                          D   0.130                                                                            0.485                                                                            0.660                                                                            0.025                                                                            3.731                                                                             0.192                                                                            0.932 0.155                                                                             1.3                                          E   0.160                                                                            0.450                                                                            0.660                                                                            0.030                                                                            2.813                                                                             0.188                                                                            0.924 0.190                                                                             1.3                                          F   0.220                                                                            0.385                                                                            0.660                                                                            0.035                                                                            1.750                                                                             0.159                                                                            0.917 0.255                                                                             1.3                                          G   0.329                                                                            0.271                                                                            0.660                                                                            0.040                                                                            0.824                                                                             0.122                                                                            0.909 0.369                                                                             1.3                                          H   0.403                                                                            0.192                                                                            0.660                                                                            0.045                                                                            0.477                                                                             0.112                                                                            0.902 0.448                                                                             1.3                                          I   0.478                                                                            0.112                                                                            0.660                                                                            0.050                                                                            0.234                                                                             0.105                                                                            0.894 0.528                                                                             1.3                                          __________________________________________________________________________     *Calculated from weights of zirconyl nitrate, aluminum nitrate, boric aci     and tetraethoxy silane.                                                  

                                      TABLE II                                    __________________________________________________________________________    Catalyst Compositions with Constant Total Moles of Metal, B, Al, Zr + Si      And Variable Moles of Zr, Si, Al/Zr, Si/Zr, (Al + Zr)/B*                                                        Total Metal,                                Catalyst                                                                          Zr Al B  Si Al/Zr                                                                             Si/Ar                                                                             (Al + Zr)/B                                                                         Zr + Si                                                                           Moles                                       __________________________________________________________________________     J+ 0.053                                                                            0.592                                                                            0.660                                                                            0.000                                                                            11.170                                                                            0.000                                                                             0.977 0.053                                                                             1.3                                         K   0.048                                                                            0.592                                                                            0.660                                                                            0.005                                                                            12.333                                                                            0.104                                                                             0.970 0.053                                                                             1.3                                         L   0.033                                                                            0.592                                                                            0.660                                                                            0.020                                                                            17.939                                                                            0.606                                                                             0.947 0.053                                                                             1.3                                         M   0.028                                                                            0.592                                                                            0.660                                                                            0.025                                                                            21.143                                                                            0.893                                                                             0.939 0.053                                                                             1.3                                         N   0.023                                                                            0.592                                                                            0.660                                                                            0.030                                                                            25.739                                                                            1.304                                                                             0.932 0.053                                                                             1.3                                         O   0.018                                                                            0.592                                                                            0.660                                                                            0.035                                                                            32.889                                                                            1.944                                                                             0.924 0.053                                                                             1.3                                         P   0.013                                                                            0.592                                                                            0.660                                                                            0.040                                                                            45.538                                                                            3.077                                                                             0.917 0.053                                                                             1.3                                         Q   0.008                                                                            0.592                                                                            0.660                                                                            0.045                                                                            74.000                                                                            5.625                                                                             0.909 0.053                                                                             1.3                                         R   0.003                                                                            0.592                                                                            0.660                                                                            0.050                                                                            197.333                                                                           16.667                                                                            0.902 0.053                                                                             1.3                                         __________________________________________________________________________     *Calculated from weights of zirconyl nitrate, aluminum nitrate, boric aci     and tetraethoxy silane.                                                       +Same as catalyst A.                                                     

The catalyst compositions described above were evaluated in a laboratoryMAT (microanalysis test) cracking test apparatus, substantially asdescribed in ASTM Method D3907, employing a hydrotreated crude oil feedhaving an API gravity of about 16 and containing about 5.4 weight %Conradson carbon, about 0.5 weight % sulfur, about 0.4 weight %nitrogen, about 1.4 weight % n-pentane insolubles, 5.5 ppm Ni, 3.1 ppmFe, and about 7.7 ppm V. The MAT tests were carried out at acatalyst:oil weight ratio of about 3:1, a reaction temperature of 950°F., a reaction time of 75 seconds, a steam-stripping cycle of 10minutes, and a regeneration cycle of 30 minutes at a temperature of1250° F. Pertinent test results (averages of at least two measurements)are summarized in Table III. The product yields were calculated bydividing the weight of a particular product component produced per hourby the weight of the oil feed which had been converted per hour.

                  TABLE III                                                       ______________________________________                                                              % Light                                                                             % Heavy                                                % Feed  %        Cycle Cycle                                             Cata-                                                                              Con-    Gasoline Oil   Oil    % Coke     Gas.                            lyst version Yield    Yield Yield  Yield MFS.sup.a                                                                          Sel..sup.b                      ______________________________________                                        A    77.4    46.2     20.6  2.0    18.0  3.4  59.7                            B    73.6    47.3     23.6  2.8    14.0  4.2  64.3                            C    74.7    47.1     23.2  2.1    15.7  4.0  63.1                            D    76.0    47.1     21.9  2.2    16.1  3.8  62.1                            E    70.7    46.7     25.7  3.6    13.8  4.2  66.1                            F    70.2    47.0     25.7  4.1    12.4  4.4  67.0                            G    73.3    46.6     23.5  3.2    14.4  4.0  63.6                            H    73.3    46.4     23.1  3.3    14.9  3.8  63.0                            I    73.3    46.7     23.1  3.0    14.9  3.9  63.2                            K    78.5    45.9     19.4  2.2    16.2  3.6  58.5                            L    73.5    48.3     23.4  3.1    12.5  4.6  65.7                            M    71.5    47.4     24.9  3.6    12.3  4.6  66.3                            N    79.9    47.3     18.8  1.4    16.1  3.8  59.3                            O    77.8    47.9     20.3  1.8    15.2  4.0  61.6                            P    75.1    48.0     22.8  2.1    15.5  4.0  64.0                            Q    66.7    43.9     26.3  7.0    12.1  3.7  65.8                            R    45.9    30.6     30.5  23.6   8.4   2.0  66.5                            ______________________________________                                         .sup.a Moter fuel selectivity is defined as the ratio of (% gasoline yiel     + % light cycle oil yield) to (% heavy cycle oil yield + % coke yield).       .sup.b Gasoline selectivity is defined as (% gasoline yield)/(%               conversion) × 100                                                  

Table III shows that catalysts B to R significantly improved gasolineselectivity over catalyst A (from 59.7% to as high as 67.0%) as well assignificantly increased the motor fuiel selectivity over catalyst A(from 3.4 to as high as 4.6).

Surface areas of the catalysts were also measured after the MAT tests.The results shown in Table IV below indicate that catalysts B to I whichcontained silicon had less change in surface area than catalyst Ademonstrating that the silicon-containing catalysts were morehydrothermally stable than the catalyst that did not contain silicon.

                  TABLE IV                                                        ______________________________________                                               Silicon                                                                             Surface Area (m.sup.2 /g)                                        Catalyst (Moles) Fresh      Post MAT                                                                             % Change                                   ______________________________________                                        A        0.000   382        241    37%                                        B        0.005   328        225    31%                                        C        0.020   365        253    31%                                        D        0.025   337        264    22%                                        B        0.030   284        189    33%                                        F        0.035   255        196    23%                                        G        0.040   346        284    18%                                        H        0.045   300        245    18%                                        I        0.050   342        273    20%                                        ______________________________________                                    

The results shown in the above examples clearly demonstrate that thepresent invention is well adapted to carry out the objects and attainthe ends and advantages mentioned as well as those inherent therein.While modifications may be made by those skilled in the art, suchmodifications are encompassed within the spirit of the present inventionas defined by the disclosure and the claims.

That which is claimed is:
 1. A composition comprising silicon, aluminum,zirconium, and borate wherein the mole ratio of aluminum to zirconium isabout 0.001:1 to about 300:1; the mole ratio of silicon to zirconium isabout 0.001:1 to about 30:1; and the mole ratio of (aluminum+zirconium)to the boron component of the borate is about 0.01:1 to about 10:1.
 2. Acomposition according to claim 1 wherein the mole ratio of aluminum tozirconium is 0.1:1 to 200:1.
 3. A composition according to claim 1wherein the mole ratio of silicon to zirconium is 0.005:1 to 20:1.
 4. Acomposition according to claim 3 wherein the mole ratio of(aluminum+zirconium) to the boron component of the borate is 0.5:1 to3:1.
 5. A composition according to claim 1 wherein said composition is acoprecipitate of silicon borate, aluminum borate, and zirconium borate.6. A composition comprising silicon, aluminum, zirconium, and boratewherein the mole ratio of silicon to zirconium is about 0.01:1 to about25:1; the mole ratio of aluminum to zirconium is about 0.01:1 to about250:1; and the mole ratio of (aluminum+zirconium) to the boron componentof the borate is about 0.1:1 to about 6:1.
 7. A composition according toclaim 6 wherein the mole ratio of silicon to zirconium is about 0.05:1to about 20:1; the mole ratio of aluminum to zirconium is 0.1:1 to 200:1; and the mole ratio of (aluminum+zirconium) to the boron component ofthe borate is 0.5:1 to 3:1.
 8. A composition according to claim 7wherein said composition is a coprecipitate of silicon borate, aluminumborate, and zirconium borate.
 9. A process comprising the step ofcontacting a silicon compound, an aluminum compound, a zirconiumcompound, and a boron compound to form a mixture and under a conditionsufficient to effect the coprecipitation of a complex metal oxidecomposition comprising silicon, aluminum, zirconium, and borate whereinthe mole ratio of aluminum to zirconium is about 0.001:1 to about 300:1;the mole ratio of silicon to zirconium is about 0.001:1 to about 30:1;and the mole ratio of (aluminum+zirconium) to the boron component of theborate is about 0.01:1 to about 10:1.
 10. A process according to claim 9wherein said silicon compound is tetraethoxy silane.
 11. A processaccording to claim 9 wherein said aluminum compound is aluminum nitrate.12. A process according to claim 9 wherein said zirconium compound iszirconyl nitrate.
 13. A process according to claim 9 wherein said boroncompound is boric acid.
 14. A process according to claim 9 wherein saidsilicon compound is tetraethoxy silane; said aluminum compound isaluminum nitrate; said zirconium compound is zirconyl nitrate and saidboron compound is boric acid.
 15. A process according to claim 9 furthercomprising the step of contacting said mixture with an alkaline aqueoussolution.
 16. A process according to claim 14 further comprising thestep of contacting said mixture with an alkaline aqueous solution.
 17. Aprocess for producing a catalyst comprising contacting catalyticallyeffective amounts of tetraethoxy silane, aluminum nitrate, zirconylnitrate, and boric acid to form a mixture and thereafter contacting saidmixture with an ammonium hydroxide solution.
 18. A compositioncomprising silicon, aluminum, zirconium, and borate wherein saidcomposition is a coprecipitate of silicon borate, aluminum borate andzirconium borate; the mole ratio of aluminum to zirconium is about0.001:1 to about 300:1; the mole ratio of silicon to zirconium is about0.001:1 to about 30:1; and the mole ratio of (aluminum+zirconium) to theboron component of the borate is about 0.01:1 to about 10:1.
 19. Acomposition according to claim 18 wherein the mole ratio of aluminum tozirconium is 0.1:1 to 200:1.
 20. A composition according to claim 18wherein the mole ratio of silicon to zirconium is 0.005:1 to 20:1.
 21. Acomposition according to claim 18 wherein the mole ratio of(aluminum+zirconium) to boron is 0.5:1 to 3:1.